When you install wp, you create a database in mysql, and create a user in mysql, and then link the two. Then you install wp.
It’s this mysql user that has disappeared. The database is still there, and I can browse that and see the 3x users I created within wordpress (or the one admin created when installing wp, and two I created). And in the sql dbase I can the posts and settings for the theme etc. No clear evidence of spam in there, just confused as to how the sql user to link with the database has gone.